The female volunteers watched sad films in isolation, capturing their tears in a vial. (AP Photo/Science)

(Newser)
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Women's tears of sadness contain a chemical signal that's a big turn-off to men, researchers were surprised to discover. Emotional tears are chemically different from tears caused by dust in the eye or chopping onions, and when male volunteers got a sniff of tears (which have no noticeable odor) collected from female volunteers watching sad movies, their testosterone levels dropped and they rated women depicted in photographs less sexually attractive than they did after sniffing saline, AP reports.

The signal may have evolved to lower aggression and display sexual disinterest, according to the lead researcher. "It is a signal that allows its user to say, 'Now is not the right time,'" he explained. It is the first such chemical signal to have been found in tears, but the researchers believe more exist. Male tears weren't tested because the team had trouble finding weepy male volunteers. But experiments are now under way "as we finally have one good man crier," noted the lead researcher.